ИСТИНА

The present invention relates to compounds according to formula I, wherein: R1 is a cyclopentadienyl moiety or a moiety comprising a cyclopentadienyl ring structure; R2 is a moiety M(R5)2 or MR5, wherein M is a metal selected from hafnium, titanium or zirconium, and R5 is F, Cl, I, Br or an alkyl-moiety comprising 1 to 10 carbon atoms, preferably methyl, benzyl, butadiene or pentadiene; R3 is H, an alkyl or aryl moiety comprising 1 to 10 carbon atoms, or a moiety comprising N or O and 1 to 15 carbon atoms; R4 is H, an alkyl or aryl moiety comprising 1 to 10 carbon atoms, or a moiety comprising N or O and 1 to 15 carbon atoms, or a halogen; wherein if R3 is H, R4 is a moiety other than H, and if R4 is H, R3 is a moiety other than H; each R6 is individually selected from H, a halogen, an alkyl moiety, an aryl moiety, a halogen-substituted alkyl moiety, a halogen-substituted aryl moiety, an alkoxy moiety, a siloxy-moiety, or a nitrogen-containing moiety, preferably H. Such compounds may be used in a catalyst system for olefin polymerisation, particularly ethylene copolymerisation, providing at least one of a high catalyst activity, a high comonomer incorporation, and/or a high molecular weight polymer.